Mixed oxides of transition metals, hydrotreatment catalysts obtained therefrom, and preparation process comprising sol-gel processes

ABSTRACT

New sulfided metal catalysts are described, containing a metal X selected from Ni, Co and mixtures thereof, a metal Y selected from Mo, W and mixtures thereof, an element Z selected from Si, Al and mixtures thereof, and possibly an organic residue, obtained by the sulfidation of mixed oxide precursors, also new, having general formula (A)
 
X a Y b Z c O d   .p C  (A)
     possibly shaped without a binder, or by sulfidation of mixed oxides having formula (A), in shaped form with a binder,   wherein X is selected from Ni, Co and mixtures thereof,   Y is selected from Mo, W and mixtures thereof,   Z is selected from Si, Al and mixtures thereof,   O is oxygen,   C is selected from:
       a nitrogenated compound N,   an organic residue deriving from the partial calcination of the nitrogenated compound N,   
       said nitrogenated compound N, when present, being selected from:   a) an alkyl ammonium hydroxide having formula (I)
 
R I R II R III R IV NOH  (I)
       wherein the groups R I R IV , the same or different, are aliphatic groups containing from 1 to 7 carbon atoms,   
       b) an amine having formula (II)
 
R 1 R 2 R 3 N  (II)
       wherein R 1  is a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, and   R 2  and R 3 , the same or different, are selected from H and a linear, branched or cyclic alkyl, containing from 4 to 12 carbon atoms, said alkyl being equal to or different from R 1 ,   
       a, b, c, d are the number of moles of the elements X, Y, Z, O, respectively,   p is the weight percentage of C with respect to the total weight of the precursor having formula (A),   a, b, c, d are higher than 0   a/b is higher than or equal to 0.3 and lower than or equal to 2,   (a+b)/c is higher than or equal to 0.3 and lower than or equal to 10, preferably varying from 0.8 to 10   d=(2a+6b+Hc)/2 wherein H=4 when Z=Si
       H=3 when Z=Al   
       and p is higher than or equal to 0 and lower than or equal to 40%.   

     Said catalysts can be used as hydrotreating catalysts.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a division of U.S. Ser. No. 13/499,452, filedJun. 11, 2012, which is a National Stage (371) of PCT/IB10/002392, filedSep. 23, 2010, which claims priority to MI2009A001680, filed Sep. 30,2009.

New sulfided metal catalysts are described, containing a metal Xselected from Ni, Co and mixtures thereof, a metal Y selected from Mo, Wand mixtures thereof, an element Z selected from Si, Al and mixturesthereof, obtained by the sulfidation of suitable precursors, whereinsaid precursors are new and are mixed oxides containing at least onemetal selected from Ni, Co and mixtures thereof, at least one metalselected from Mo, W and mixtures thereof, at least one element selectedfrom Si, Al and mixtures thereof, and possibly containing a nitrogenatedcompound or an organic residue coming from the partial calcination ofthe nitrogenated compound. Suitable methods are also described for thepreparation of said sol-gel precursors. The catalysts obtained by thesulfidation of these precursors can be used as hydrotreatment catalysts.

It has been known since the beginning of the last century thattransition metals are converted to catalytic materials of the TMS type(Transmission Metal Sulfide) in the presence of heavy oil fractions richin sulfur. The work of M. Pier, Z. Elektrochem., 35 (1949), 291, isparticularly important, after which TMS catalysts, such as MoS₂ and WS2,became the basis of modern catalysts supported on alumina, Co and Niacting as promoters.

TMS of the second or third transition series, such as RuS2 and Rh₂S₃have proved to be extremely active and stabile catalysts inhydrotreatment processes, as they are based on precious metals, however,they have not found a widespread industrial application. Consequently,in all refinery processes in which unitary hydrotreatment operationsmust be performed, whether they be hydrogenation or sulfur and nitrogenremoval, the preferred catalysts are based on Mo and W. Furthermore,both Co and Ni are used for promoting the catalyst activity. Thepromoter allows an increase in the catalytic activity to be obtained,which depends on the preparation details, the type of material and otherfactors, but which can reach a factor 10-12 times higher with respect tothat of a catalyst without a promoter (H. Topsoe, B. S. Clausen, F. E.Massoth, in Catalysis, Science and Technology, vol. 11, J. R. Andersonand M. Boudard Eds., (Springer-Verlag, Berlin 1996)).

This phenomenon is called synergetic effect and implies that thepromoter and base metal act together.

The increasingly strict regulations on gaseous emissions, however, makeit necessary to resort to even more highly active catalysts. Inparticular, in gas oil for motor vehicles, the recent Europeanregulation envisages a sulfur content ≤10 ppm. To be able to go belowthese levels, catalysts must be found that are capable of decomposingcompounds which are particularly difficult to treat, such as stericallyhindered dibenzothiopnenes. In addition, the catalyst must also beactive with respect to compounds containing other neteroatoms, nitrogenin particular, which tend to deactivate the functionality with respectto compounds containing sulfur.

A recent development relates to the application of catalysts whichcomprise a non-noble metal of Group VIII and two metals of Group VIB.Catalysts of this type and the their preparation are described, forexample, in patents JP 0 9000929, U.S. Pat. No. 4,596,785, U.S. Pat. No.4,820,677, U.S. Pat. No. 6,299,760, U.S. Pat. No. 6,635,599, US2007/0286781, EP 1941944. In particular, as far as the preparations areconcerned, JP 09000929 describes a process for impregnation of aninorganic carrier with Co (or Ni), Mo and W. U.S. Pat. No. 4,596,785 andU.S. Pat. No. 4,820,677 describe co-precipitation techniques of therelative sulfides, which therefore require process phases in inertatmospheres. U.S. Pat. No. 6,299,760 and U.S. Pat. No. 6,635,599describe co-precipitation methods with the use of complexing agents,from aqueous solutions heated to around 90° C. US 2007/0286781 alsodescribes a preparation process for materials based on transitionmetals, using co-precipitation techniques. In patent EP 1941944,co-precipitation techniques are coupled with heating phases torelatively high temperatures.

None of these processes, however, allows an accurate control on thestoichiometry of the final material.

EP 340868 describes a sol-gel process for the preparation of amicro-mesoporous silica and alumina gel, amorphous to X-rays, having aSiO₂/Al₂O₃ molar ratio within the range of 30 to 500, a surface areawithin the range of 500 to 1,000 m²/g and a pore volume ranging from0.3-0.6 ml/g.

U.S. Pat. No. 5,914,398 describes a sol-gel process for the preparationof a micro-mesoporous silico-alumina.

In patent EP 0972568, a sol-gel process is described for obtaining acatalyst containing molybdenum with a surface area ranging from 20 to400 m²/g and a Mo/Si molar ratio >0.2, exemplified up to 4.5. This is aspecific catalyst for the isomerization of n-paraffins.

It has now been found that, through a particular and calibrated sol-gelsynthesis, it is possible to prepare mixed oxides containing suitabletransition metals (TM) of Groups VIII and VIB and containing siliconand/or aluminium, in a too high TM/Si or TM/Al molar ratio, at the sametime maintaining high values of the specific surface areas and totalpore volume. The preparation of all these mixed oxides is effectedthrough the synthesis of precursors containing a gelling agent. Theseprecursors containing the gelling agent, and the mixed oxides obtainedtherefrom, possibly after shaping process, are transformed “in situ”into the relative sulfides, i.e. in the same environment in which thehydrotreatment is effected, or “ex situ”. The sulfides thus obtained areactive as catalysts in hydrotreatment processes, in particularsimultaneous hydrosulfurization and hydrodenitrification processes.

A first object of the present invention therefore relates to new mixedoxides, which can be used, after sulfidation, as hydrotreatmentcatalyst, having general formula (A):X_(a)Y_(b)Z_(c)O_(d) .pC  (A)possibly shaped without a binder,wherein X is selected from Ni, Co and mixtures thereof,Y is selected from Mo, W and mixtures thereof,Z is selected from Si, Al and mixtures thereof,O is oxygen,C is selected from:

-   -   a nitrogenated compound N,    -   an organic residue deriving from the partial calcination of the        nitrogenated compound N,        wherein said nitrogenated compound N is selected from:        a) an alkyl ammonium hydroxide having formula (I)        R^(I)R^(II)R^(III)R^(IV)NOH  (I)    -   wherein the groups R^(I), R^(II), R^(III) and R^(IV), the same        or different, are aliphatic groups containing from 1 to 7 carbon        atoms,        b) an amine having formula (II)        R¹R²R³N  (II)    -   wherein R¹ is a linear, branched or cyclic alkyl, containing        from 4 to 12 carbon atoms, and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl, containing from 4 to 12 carbon        atoms, said alkyl being equal to or different from R¹,        a, b, c, d are the number of moles of the elements X, Y, Z, O,        respectively,        p is the weight percentage of C with respect to the total weight        of the compound having formula (A),        a, b, c, d are higher than 0        a/b is higher than or equal to 0.3 and lower than or equal to 2,        (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10, preferably varying from 0.8 to 10        d=(2a+6b+Hc)/2 wherein H=4 when Z=Si    -   H=3 when Z=Al        and p is higher than or equal to 0 and lower than or equal to        40%.

The organic residues deriving from the nitrogenated compounds N bypartial calcination, are residues containing carbon and nitrogen.

When C is the nitrogenated compound N, its weight percentage preferablyranges from 10 to 35%; when C is the organic residue deriving from thepartial calcination of the nitrogenated compound N, its weightpercentage is preferably higher than 0 and lower than or equal to 25%.

Compounds having formula (A) shaped without a binder refer to compoundshaving formula (A) in the form suitable for being industrially used in areactor and without the addition of a binder, i.e. without the use of abinder during the shaping procedure.

All shaping techniques without a binder can be used for this purpose.Particular new shaping techniques are described hereunder.

The compounds having formula (A) are transformed into the relativesulfides, active as hydrotreatment catalysts, by means of sulfidation:the sulfided metal compounds, called (A)S, containing a metal X selectedfrom Ni, Co and mixtures thereof, a metal Y selected from Mo and W andmixtures thereof, an element Z selected from Si, Al and mixturesthereof, and possibly an organic residue, obtained by sulfidation of theprecursor compounds having formula (A), possibly shaped without abinder, or precursor having formula (A) in shaped form with a binder,are, in turn, new and represent a further object of the presentinvention.

Hydrotreatment refers to a process in which a hydrocarbon feed isconverted in contact with hydrogen, at a high temperature and pressure.During the hydrotreatment, various reactions can take place, forexample, hydrogenation, or isomerization, hydrodesulfurization,hydrodenitrogenation, according to the catalytic system and operatingconditions used. The sulfided catalysts of the present invention,obtained by sulfidation of the precursors having formula (A), are activein hydrotreatment and particularly selective in hydrodesulfurization andhydrodenitrogenation reactions.

A particular object of the present invention relates to new mixed oxideswhich can be used, after sulfidation, as hydrotreatment catalysts,having the general molar formula (A1):X_(a)Y_(b)Z_(c)O_(d)  (A1)possibly shaped without a binder, wherein X is selected from Ni, Co andmixtures thereof,Y is selected from Mo, W and mixtures thereof,Z is selected from Si, Al and mixtures thereof,O is oxygena, b, c, d are the number of moles of the elements X,Y, Z, O, respectively and are higher than 0a/b is higher than or equal to 0.3 and lower than or equal to 2,(a+b)/c is higher than or equal to 0.3 and lower than or equal to 10,and preferably varies from 0.8 to 10,d=(2a+6b+Hc)/2 wherein H=4 when Z=Si

-   -   H=3 when Z=Al

These oxides (A1) are preferably mesoporous, have a surface area,determined after thermal treatment at 550° C., higher than or equal to70 m²/g and a pore volume higher than or equal to 0.10 ml/g.

In accordance with the IUPAC terminology “Manual of Symbols andTerminology” (1972), Appendix 2, Part I Coll. Surface Chem. Pure Appl.Chem., Vol. 31, page 578, wherein micropores are defined as pores havinga diameter smaller than 2 nm, mesopores are defined as pores having adiameter ranging from 2 to 50 nm, macropores are those having a diameterlarger than 50 nm, the mixed oxides of the present invention havingformula (A1) are mesoporous, and are characterized by an irreversibleisotherm, of type IV. The average pore diameter is preferably within therange of 3 to 18 nm.

The compounds having formula (A1) are also transformed into the relativesulfides by means of sulfidation: the sulfided metal compounds,indicated, as (A1)S, containing a metal X selected from Ni, Co andmixtures thereof, a metal Y selected from Mo and W and mixtures thereof,an element Z selected from Si, Al and mixtures thereof, obtained bysulfidation of the precursor compounds having formula (A1), possiblyshaped without a binder, or compounds having formula (A1) in shaped formwith a binder, are in turn new and represent a further object of thepresent invention. These particular sulfided compounds are in turnactive as hydrotreatment catalysts.

Another particular object of the present invention relates to new mixedoxides, which can be used, after sulfidation, as hydrotreatmentcatalysts, having general formula (A2):X_(a)Y_(b)Z_(c)O_(d) .pC  (A2)possibly shaped without a binder,wherein X is selected from Ni, Co and mixtures thereof,Y is selected from Mo, W and mixtures thereof,Z is selected from Si, Al and mixtures thereof,O is oxygenC is selected from:

-   -   a nitrogenated compound N,    -   an organic residue deriving from the partial calcination of the        nitrogenated compound N,        wherein said nitrogenated compound is selected from:        a) an alkyl ammonium hydroxide corresponding to formula (I)        R^(I)R^(II)R^(III)R^(IV)NOH  (I)    -   wherein the groups R^(I), R^(II), R^(III) and R^(IV), the same        or different, are aliphatic groups containing from 1 to 7 carbon        atoms,        b) an amine having formula (II)        R¹R²R³N  (II)    -   wherein    -   R¹ is a linear, branched or cyclic alkyl, containing from 4 to        12 carbon atoms and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl, containing from 4 to 12 carbon        atoms, said alkyl being equal to or different from R¹,        a, b, c, d are the number of moles of the elements X,        Y, Z, O, respectively,        p is the weight percentage of C with respect to the total weight        of the compound having formula (A2),        a, b, c, a are higher than 0        a/b is higher than or equal to 0.3 and lower than or equal to 2,        (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10, preferably ranges from 0.8 to 10        d=(2a+6b+Hc)/2 wherein H=4 when Z=Si    -   H=3 when Z=Al        and p is higher than 0 and lower than or equal to 40%.

Said oxides (A2) are preferably mesoporous, have a surface area,determined after thermal treatment at 400° C., higher than or equal to90 m²/g and a pore volume higher than or equal to 0.18 ml/g. Inparticular, when Z is silicon, the surface area is preferably higherthan or equal to 110 m²/g and the pore volume higher than or equal to0.20 ml/g, and when Z is Al, the surface area is preferably higher thanor equal to 130 m²/g and the pore volume higher than or equal to 0.30ml/g.

The compounds having formula (A2) are also transformed into the relativesulfides by means of sulfidation: the sulfided metal compounds,indicated as (A2)S, containing a metal X selected from Ni, Co andmixtures thereof, a metal Y selected from Mo and W and mixtures thereof,an element Z selected from Si, Al and mixtures thereof, possibly anorganic residue, obtained by sulfidation of the precursor compoundshaving formula (A2), possibly shaped without a binder, or compoundshaving formula (A2) in shaped form with a binder, are in turn new andrepresent a further object of the present invention. These particularsulfided compounds are active as hydrotreatment catalysts.

Compounds having formula (A1) and (A2) shaped without a binder refer tocompounds having formula (A1) and (A2) in a form, suitable for beingused in a chemical reactor, without the addition, of a binder, i.e.without the addition of a binder in the shaping process: said shapingprocess without the addition of a binder can be effected with anytechnique known to experts in the field. Particular shaping processesare described hereunder and are a further object of the presentinvention.

According to what, is described above, the family of precursors havingformula (A) is therefore composed of precursors having formula (A1) and(A2), the latter containing a nitrogenated compound N selected fromcompounds having formula (I) and (II) or an organic residue derivingfrom the partial calcination of the nitrogenated compound.

With reference; to formulae (A), (A1) e (A2), a preferred aspect is thatthe nitrogenated compounds having formula (I) are tetra-alkyl ammoniumhydroxides, wherein the alkyl groups, the same as each other, containfrom 1 to 7 carbon atoms, or trimethylalkyl ammonium hydroxides, whereinthe alkyl group contains from 1 to 7 carbon atoms. Tetrapropyl ammoniumhydroxide is preferably used.

According to another preferred aspect, the nitrogenated compounds havingformula (II) are selected from n-hexylamine, n-heptylamine andn-octylamine.

According to another preferred aspect, the organic

residues deriving from the partial calcination of the nitrogenatedcompounds are residues containing carbon and nitrogen.

With reference to the formulae (A), (A1) and (A2), a preferred aspect isthat X is Ni.

When, in the formulae (A), (A1) and (A2), X is a mixture of Ni and Co,the molar ratio Ni/Co preferably varies within the range of 100/1 to1/100, even more preferably within the range of 10/1-1/10.

When Y is a mixture of Mo and W, in the formulae (A), (A1) and (A2),their molar ratio Mo/W preferably varies within the range of 100/1 to1/100, even more preferably within the range of 10/1-1/10.

The mixed oxides having formula (A), (A1) and (A2), therefore contain,in addition to the element Z, at least one element selected from Ni andCo, and at least one element selected from Mo and W, and preferablycontain at least one element selected from Ni and Co and a mixture of Moand W. Compositions containing a mixture of Co and Ni and a mixture ofMo and W are also preferred.

Once the oxides having formula (A), (A1) and (A2), possibly shapedwithout a binder, or in shaped form with a binder, have been transformedinto the corresponding sulfides (A)S, (A1)S and (A2)S, they becomeactive catalysts in simultaneous hydrodesulfurization andhydrodenitrification processes.

The sulfidation of the compounds having formula (A) of the presentinvention, possibly shaped without a binder, or in shaped form with abinder, for obtaining the corresponding sulfided compositions which area further object of the present invention and are active ashydrotreatment catalysts, is effected using any of the techniques knownto experts in the field. In particular, the sulfidation can be carriedout “ex situ” or “in situ”, i.e. in the same reactor in which thehydrotreatment is subsequently effected. The sulfidation process can becarried out in a reducing atmosphere, for example consisting of H₂S andhydrogen, or CS₂ and hydrogen, at a high temperature, for exampleranging from 300° to 500° C., for a period sufficient for sulfiding thestarting mixed oxide, for example from 1 to 100 hours. Alternatively,the sulfidation can also be carried out using dimethyl disulfidedissolved in a hydrocarbon charge, such as naphtha or gas oil, at atemperature ranging from 300° to 500° C. Finally, the sulfidation can becarried out using the sulfur present in the charge to be treateddirectly, preferably at a temperature ranging from 300° to 500° C.

Sulfidation techniques which can be well used for transforming the mixedoxides of the present invention into the corresponding sulfides are alsodescribed, for example, in “Petroleum Refining”, J. H. Gary, G. E.Handwerk, M. Dekker Ed. 1994.

The compounds having formula (A) of the present

invention, and therefore the compounds having formula (A1) and (A2), alluseful as precursors of the corresponding sulfided metallic compositionsof the present invention, can be prepared simply and economically,guaranteeing a strict control of the stoichiometry of the oxides,without any separation and washing operations of the solid phasesobtained.

The elimination of these phases allows the total recovery of thetransition metals present in the reagent mixture. Analytic controls fordetermining the final composition of the oxide are therefore no longernecessary and the production of water polluted with salts of transitionmetals is also avoided, this is a particularly important aspect from anindustrial point of view considering the classification of these saltsas carcinogenic or potentially carcinogenic.

A further object of the present invention therefore relates to a sol-gelprocess, called SG process, for the preparation of mixed oxides havingformula (A): the process comprises the preparation of mixed oxideshaving formula (A2), containing the nitrogenated compound N, which canbe partially calcined to give the corresponding compounds having formula(A2) wherein C is an organic residue deriving from the partialcalcination of the nitrogenated compound, or transformed into the mixedoxides having formula (A1) by total calcination.

Said sol-gel process for the preparation of mixed

oxides having formula (A), called SG, therefore comprises:

-   -   preparing a hydro-alcohol solution/suspension containing at        least one soluble or partially soluble source of at least one        element X, at least one soluble or partially soluble source of        at least one element Y, at least one soluble source, which can        be hydrolyzed or dispersed, of at least one element Z and a        nitrogenated compound N selected from:        a) an alkyl ammonium, hydroxide having formula (I)        R^(I)R^(II)R^(III)R^(IV)NOH  (I)    -   wherein the groups R^(I)-R^(IV), the same or different, are        aliphatic groups containing from 1 to 7 carbon atoms,        b) an amine having formula (II)        R¹R²R³N  (II)    -   wherein R¹ is a linear, branched or cyclic alkyl, containing        from 4 to 12 carbon atoms, and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl, containing from 4 to 12 carbon        atoms, said alkyl being equal to, or different from, R¹;        wherein the molar ratio N/(X+Y) is higher than 0 and lower than,        or equal to 1, and preferably higher than 0.1;    -   obtaining the formation of a gel,    -   maintaining the gel under stirring preferably at a temperature        ranging from 25 to 70° C. and for a time ranging from 1 to 48        hours,    -   maintaining the gel under static conditions, preferably at room        temperature and for a period ranging from 24 to 100 hours,    -   drying the gel prepared in the previous step, obtaining the        mixed oxide precursor having the molar formula (A2)        X_(a)Y_(b)Z_(c)O_(d) .pC  (A2)        wherein X is selected from Ni, Co and mixtures thereof,        Y is selected from Mo, W and mixtures thereof,        Z is selected from Si, Al and mixtures thereof,        O is oxygen,        C is a nitrogenated compound N selected from the nitrogenated        compounds mentioned above, having formula (I) or (II),        a, b, c, d are the number of moles of the elements X, Y, Z and        O, respectively,        P is the weight percentage of C with respect to the total weight        of the compound having formula (A2)        a, b, c, d are higher than 0        a/b is higher than or equal to 0.3 and lower than or equal to 2,        (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10 and preferably ranges from 0.8 to 10,        d=(2a+6b+Hc)/2 wherein H=4 when Z=Si        H=3 when Z=Al        and p is higher than 0 and lower than or equal to 40%,

possibly subjecting the compound of formula (A2) resulting from, theprevious step, to partial or total calcination, respectively obtaining acompound having the same formula (A2) wherein C is an organic residuederiving from the calcination of the nitrogenated compound, or a mixedoxide of formula (A1)X_(a)Y_(b)Z_(c)O_(d)  (A1)wherein X, Y, Z, O, a, b, c, d correspond to those of the previousformula (A2).

Once the hydroalcohol solution/suspension has been prepared, theformation of the gel is spontaneous and can be either instantaneous orrequire up to 60 minutes of time, preferably under stirring.

Suitable sources of the metal Y are, for example, the correspondingacids, oxides and salts of ammonium. Ammonium heptamolybdate ispreferably used as molybdenum salt and ammonium metatungstate astungsten salt.

Suitable sources of the metal X are, for example, the correspondingnitrates, acetates, hydroxy carbonates, carbonates, acetylacetonates.Nitrates or acetates of Ni or Co are preferably used.

When, in particular, a mixed oxide containing at least one elementselected from Ni and Co and a mixture of Mo and W, is desired, sourcesof both metals Mo and W will be present, whereas there will be thesource of only one metal X; when a mixed oxide containing a mixture ofCo and Ni and a mixture of Mo and W is prepared, sources of both metalsMo and W will be present and sources of both metals Co and Ni.

When X is a mixture of Ni and Co, the Ni/Co molar ratio in the reactionmixture preferably ranges from 100/1 to 1/100.

When Y is a mixture of Mo and W, the Mo/W molar ratio in the reaction,mixture preferably ranges from 100/1 to 1/100.

When Z is silicon, colloidal silicas, fumed silica and tetra-alkylorthosilicates in which the alkyl group contains from 1 to 4 carbonatoms, can be suitably used as corresponding soluble, dispersible orhydrolyzable compounds.

Hydrolyzable silicas, which, starting from monomeric precursors ofsilicon, guarantee a better dispersion in the gel, are preferably used.Tetraethyl orthosilicate is more preferably used.

When Z is aluminium, aluminium lactate can be suitably used as solublecompounds and, as corresponding dispersible or hydrolyzable compounds,dispersible aluminas, monohydrated aluminas AlOOH, trihydrated alumninasAl(OH)₃, aluminium oxide, aluminium trialkoxides wherein the alkyl islinear or branched and can contain from 2 to 5 carbon atoms.

The dispersible aluminas are preferably bohemites or pseudo-bohemitescharacterized by particles with an average diameter of less than 100microns. Dispersible aluminas which can be suitably used are for examplebohemites of the series Versal®, Pural®, Catapal®, Disperal® andDispal®.

Particularly preferred among dispersible aluminas are aluminasdispersible at room temperature in the presence of stirring in water orin aqueous solution containing a monovalent acid: in the dispersed phasethese aluminas are nanodimensional, characterized by dimensions of thedispersed particles ranging from 10 to 500 nm. Dispersible aluminas ofthis type which can be suitably used are, for example, bohemites of theseries Disperal® and Dispal®.

Hydrolyzable aluminas, which, starting from, monomeric precursors ofaluminium, guarantee a good dispersion in the gel, are preferablytrialkyl aluminates in which the alkyl group contains from 3 to 4 carbonatoms.

In the drying step, the gel is dried, preferably at a temperatureranging from 80 to 120° C., with the formation of a compound havingformula (A2) wherein C is the nitrogenated compound N.

According to what is specified above, the first five steps of theprocess allow to prepare compounds having formula (A2), wherein C is thenitrogenated compound N, which can be used as such, or, after shaping,directly for preparing the sulfided catalysts of the present invention,or they can be subjected to the subsequent step of at least partialcalcination.

In the last step, a total calcination, i.e. such as to completely removethe nitrogenated compound, effected at a temperature of at least 450°C., preferably higher than or equal to 450° C. and lower than or equalto 600° C., in air or inert atmosphere, allows the mixed oxides havingformula (A1) to be obtained:X_(a)Y_(b)Z_(c)O_(d)  (A1)wherein X is selected from Ni, Co and mixtures thereof,Y is selected from Mo, W and mixtures thereof,Z is selected from Si, Al and mixtures thereof,O is oxygena, b, c and d are the number of moles of the elementsX, Y, Z, O, respectivelya, b, c, d are higher than 0a/b is higher than or equal to 0.3 and lower than or equal to 2,(a+b)/c is higher than or equal to 0.3 and lower than or equal to 10,and preferably varies from 0.8 to 10,d=(2a+6b+Hc)/2 wherein H=4 when Z=Si

-   -   H=3 when Z=Al

Said mixed oxides, after possible shaping without a binder, or aftershaping with a binder, can be sulfided to give in turn the catalysts ofthe present invention.

The calcination of the compound having formula (A2) can also be effectedpartially, at a temperature lower than 450° C. in air or in an inertatmosphere, preferably at a temperature lower than or equal to 400° C.,even more preferably at a temperature ranging from 200 to 400° C.; theresulting product, containing an organic residue deriving from thecalcination of the nitrogenated compound, is again of the type (A2), andcan therefore be used in turn, after possible shaping without a binderor in the presence of a binder, for preparing the sulfided catalysts ofthe present invention, by sulfidation.

The gel obtained from the fourth step of the preparation processdescribed above, also called aging step, which has not undergone drying,can also be used for preparing the sulfided catalysts of the presentinvention. In this case said gel must be subjected to shaping processbefore to be sulfided; the water contained therein will therefore beremoved, thus causing, together with the shaping, a kind of drying,consequently generating, by means of an alternative synthesis, shapedcompounds of the type (A2), wherein C is the nitrogenated compound N.

The particular preparation of the mixed oxides of the present inventionhaving formula (A), (A1) and (A2) does not involve washing andfiltration phases, and therefore guarantees the homogeneity of thecomposition and maintenance of the starting stoichiometry.

Furthermore, this particular preparation allows mixed oxides havingformula (A1) having a high porosity and high surface area, to beobtained.

According to the general method described above, a particular object ofthe present invention relates to a sol-gel process, called SG-I, for thepreparation of mixed oxides having formula (A) which comprises thefollowing phases:

1) an aqueous solution (a) is prepared of at least one soluble orpartially soluble source of at least one metal Y, and alkyl ammoniumhydroxide, having the formulaR^(I)R^(II)R^(III)R^(IV)NOH  (I)wherein the groups R^(I)-R^(IV), the same or different, are aliphaticgroups containing from 1 to 7 carbon atoms, is added to this solution,2) a solution/suspension (b) in alcohol is prepared, preferably ethylalcohol, of a hydrolyzable or dispersible soluble compound of theelement Z and of at least a soluble or partially soluble source of atleast one metal X;3) the solution (a) and the solution/suspension (b) are mixed, obtainingthe formation of a gel;4) the gel is maintained under stirring, preferably at a temperatureranging from 25 to 70° C. and for a time ranging from 1 to 48 hours,5) the gel is maintained under static conditions, preferably at roomtemperature for a period ranging from 24 to 100 hours,6) the gel resulting from step (5) is dried, obtaining a mixed oxidehaving the molar formula (A2)X_(a)Y_(b)Z_(c)O_(d) .pC  (A2)wherein X is selected from Ni, Co and mixtures thereof,Y is selected from Mo, W and mixtures thereof,Z is selected from Si, Al and mixtures thereof,O is oxygen,C is a nitrogenated compound having formula (I),a, b, c and d are the number of moles of the elements X, Y, Z and O,respectively,p is the weight percentage of C with respect to the total weight of thecompound of formula (A2)a, b, c, d are higher than 0a/b is higher than or equal to 0.3 and lower than or equal to 2,(a+b)/c is higher than or equal to 0.3 and lower than or equal to 10,and preferably ranges from 0.8 to 10d=(2a+6b+Hc)/2 wherein H=4 when Z=Si

-   -   H=3 when Z=Al        p is higher than 0 and lower than or equal to 40%,        7) the product obtained from step (6) is possibly subjected to        partial or total calcination, obtaining, respectively, a        compound having the same molar formula (A2) wherein C is an        organic residue deriving from the calcination of the        nitrogenated compound, or a mixed oxide having formula (A1):        X_(a)Y_(b)Z_(c)O_(d)  (A1)        wherein X is selected from Ni, Co and mixtures thereof,        Y is selected from Mo, W and mixtures thereof,        Z is selected from Si, Al and mixtures thereof,        O is oxygen        a, b, c, d are the number of moles of the elements X, Y, Z, O,        respectively and are higher than 0        a/b is higher than or equal to 0.3 and lower or equal to 2,        (a+b)/c is higher than or equal to 0.3 and lower than 10 or        equal to 10 and preferably ranges from 0.8 to 10        d=(2a+6b+Hc)/2 wherein H=4 when Z=Si    -   H=3 when Z=Al.

All the aspects, conditions and reagents described for the general SGsynthesis, are valid for this particular synthesis. In phase (1)alkylammonium hydroxides which can be suitably used are preferablytetra-alkylammonium hydroxides, wherein the alkyl groups, the same aseach other, contain from 1 to 7 carbon atoms, and trimethylalkylammoniumhydroxides, wherein the alkyl group contains from 1 to 7 carbon atoms.Tetrapropylamonium hydroxide is preferably used.

In step (3) the ratios between the reagents, expressed as molar ratiosof the elements, are the following:X/Y=0.3-2R^(I)R^(II)R^(III)R^(IV)NOH/(X+Y)=0.1-0.6(X+Y)/Z is higher than or equal to 0.3 and lower than or equal to 10H₂O/(X+Y+Z)>10Alcohol/H₂O=0-1

Even more preferably, the following molar ratios between the elements instep (3) are used:X/Y=0.3-2R^(I)R^(II)R^(III)R^(IV)NOH/(X+Y)=0.1-0.4(X+Y)/Z is higher than or equal to 0.8 and lower than or equal to 10H₂O/(X+Y+Z)>10, more preferably ranges from 15-53Alcohol/H₂O=0.1-0.6, more preferably 0.25-0.4.

Step (3) is effected by adding one solution to the other; the mixingorder does not jeopardize the preparation procedure.

In step (3), preferably carried out under stirring, the hydrolysis andpolycondensation of the element Z source take place with the formationof a gel. The formation of the gel can be instantaneous or require up to60 minutes of time. The gel maintained under stirring in step (4) isthen kept under static conditions in step (5), called aging step. Instep (6), the gel is then dried, preferably at a temperature rangingfrom 80 to 120° C., with the formation of a compound having formula (A2)which, in step 7, is at least partially calcined. The total or partialcalcination is effected as previously described for the general SGsynthesis.

According to another preferred aspect of the present invention, theamine having formula (II) is used in the preparation of the mixed oxidesof the present invention. This preparation, in the case of mixed oxidescomprising silicon, is indicated as SG-II-Si and comprises the followingphases:

a) a solution (C) is prepared in alcohol, preferably ethyl alcohol, of ahydrolyzable or dispersible compound of silicon, and an amine havingformula (II) is also added to this solutionR¹R²R³N  (II)

-   -   wherein    -   R¹ is a linear, branched or cyclic alkyl, containing from 4 to        12 carbon atoms, and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl containing from 4 to 12 carbon        atoms, said alkyl being the same or different from R¹;        b) a solution/aqueous suspension (D) is prepared of at least one        source of at least one metal X and of at least one source of at        least one metal Y;        c) the solution (C) and the solution/suspension (D) are mixed        until a gel is formed;        d) the gel is maintained under stirring, preferably at a        temperature ranging from 25 to 70° C., for a time ranging from 1        to 48 hours,        e) the gel is maintained under static conditions, preferably at        room temperature for a period ranging from 24 to 100 hours,        f) the gel resulting from step (e) is dried, obtaining a mixed        oxide precursor having the molar formula (A2)        X_(a)Y_(b)Z_(c)O_(d) .pC  (A2)        wherein X is selected from Ni, Co and mixtures thereof,    -   Y is selected from. Mo, W and mixtures thereof,    -   Z is Si,    -   O is oxygen,    -   C is a nitrogenated compound having formula (II),    -   a, b, c, d are the number of moles of the elements X, Y, Z and        O, respectively,    -   p is the weight percentage of C with respect to the total weight        of the compound of formula (A2)    -   a, b, c and a are higher than 0    -   a/b is higher than or equal to 0.3 and lower than or equal to 2,    -   (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10 and preferably varies from 0.8 to 10,    -   d=(2a+6b+Hc)/2 wherein H=4    -   p is higher than 0 and lower than or equal to 40%,        g) the product obtained in the previous step is possibly        subjected to partial or total calcination, obtaining,        respectively, a mixed oxide having the same molar formula (A2)        wherein C is an organic residue deriving from the partial        calcination of the nitrogenated compound N, or a mixed oxide        having the molar formula (A1):        X_(a)Y_(b)Z_(c)O_(d)  (A1)    -   wherein X is selected from Ni, Co and mixtures thereof,    -   Y is selected from Mo, W and mixtures thereof,    -   Z is Si    -   O is oxygen    -   a, b, c and d are the number of moles of the elements X, Y, Z,        O, respectively    -   a, b, c, d are higher than 0    -   a/b is higher than or equal to 0.3 and lower than    -   (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10, and preferably ranges from 0.8 to 10,    -   d=(2a+6b+Hc)/2 wherein H=4.

All the aspects, conditions and reagents described for the general SGsynthesis, are valid for this particular synthesis.

The amine is preferably selected from n-hexylamine, n-heptylamine andn-octylamine.

In the mixing and stirring phase (c), the ratios between the reagents,expressed as molar ratios, are the following:X/Y=0.3-2R¹R²R³N/(X+Y)=0.1-1,more preferably 0.15-0.7(X+Y)/Si is higher than or equal to 0.3 and lower than or equal to 10and preferably ranges from 0.8 to 10, H₂O/(X+Y+Si)≥10, and morepreferably ranges from 15-30 Alcohol/H₂O=0-0.4, more preferably 0.2-0.4.

In step (c), the hydrolysis and polycondensation of the silicon sourcetake place with the formation of a gel. The formation of the gel can beinstantaneous or require up to 60 minutes of time. The gel maintainedunder stirring in step (d) is then aged i.e. kept under staticconditions, in step (e). In step (f), the gel is then dried, preferablyat a temperature ranging from 80 to 120° C., with the formation of acompound having formula (A2). This compound is subjected to at leastpartial calcination in the subsequent step (g). The total or partialcalcination is effected as previously described for the general SGsynthesis.

In the case of mixed oxides containing aluminium as 15 component Z, thesynthesis procedure, indicated as SG-II-Al, which uses an amine becomesthe following:

a) a solution (C) is prepared in alcohol, preferably ethyl alcohol, ofan amine having formula (II)R¹R²R³N  (II)

-   -   wherein    -   R¹ is a linear, branched or cyclic alkyl, containing from 4 to        12 carbon atoms, and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl containing from 4 to 12 carbon        atoms, said alkyl being the same or different from R¹;        b) a solution/aqueous suspension (D) is prepared of soluble or        partially soluble sources of at least one metal X, at least one        metal Y and a hydrolyzable compound of aluminium;        c) the solution (C) and the solution/suspension (D) are mixed        until a gel is formed;        d) the gel is maintained under stirring, preferably at a        temperature ranging from 25 to 70° C., for a time ranging from 1        to 48 hours,        e) the gel is maintained, under static conditions, preferably at        room temperature for a period of 24 to 100 hours,        f) the gel resulting from step (e) is dried, obtaining a        precursor mixed oxide having the molar formula (A2)        X_(a)Y_(b)Z_(c)O_(d) .pC  (A2)    -   wherein X is selected from Ni, Co and mixtures thereof,    -   Y is selected from Mo, W and mixtures thereof,    -   Z is Al,    -   O is oxygen,    -   C is a nitrogenated compound having formula (II),    -   a, b, c and d are the number of moles of the elements X, Y, Z        and O, respectively,    -   p is the weight percentage of C with respect to the total weight        of the compound of formula (A2)    -   a, b, c, d are higher than 0    -   a/b is higher than or equal to 0.3 and lower than or equal to 2,    -   (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10, and preferably varies from 0.8 to 10,    -   d=(2a+6b+Hc)/2 wherein H=3    -   p is higher than 0 and lower than or equal to 40%,        g) the product obtained in the previous step is possibly        subjected to partial or total calcination, obtaining,        respectively, a mixed oxide having the same molar formula (A2)        wherein C is an organic residue deriving from the partial        calcination of the nitrogenated compound, or a mixed oxide        having the formula (A1):        X_(a)Y_(b)Z_(c)O_(d)  (A1)    -   wherein X is selected from Ni, Co and mixtures thereof,    -   Y is selected from Mo, W and mixtures thereof,    -   Z is Al    -   O is oxygen    -   a, b, c, a are the number of moles of the elements X, Y, Z, O,        respectively    -   a, b, c, a are higher than 0    -   a/b is higher than or equal to 0.3 and lower than or equal to 2,    -   (a+b)/c is higher than or equal to 0.3 and lower than or equal        to 10, and preferably varies from 0.8 to 10,    -   d=(2a+6b+Hc)/2 wherein H=3.    -   All the aspects, conditions and reagents described for the        general SG synthesis, are valid for this particular synthesis.

In phase (a), the amine is preferably selected from n-hexylamine,n-heptylamine and n-octylamine.

In phase (c), the ratios between the reagents, expressed as molarratios, are the following:X/Y=0.3-2R¹R²R³N/(X+Y)=0.1-1and preferably 0.15-0.6(X+Y)/Al is higher than or equal to 0.3 and lower than or equal to 10and preferably varies from 0.8 to 10H₂O/(X+Y+Al)≥10 and preferably ranges from 10 to 30 Alcohol/H₂O=0-1 andpreferably ranges from 0.2 to 0.7.

Step (c) is effected by adding one solution to the other; the mixingorder does not jeopardize the preparation procedure.

In step (c), the hydrolysis and polycondensation of the aluminium sourcetake place with the formation of a gel. The formation of the gel can beinstantaneous or require up to 60 minutes of time. The gel maintained 20under stirring in step (d) is then aged, i.e. maintained under staticconditions in step (e).

In step (f), the gel is then dried, preferably at a temperature rangingfrom 80 to 120° C., and at least partially calcined in air or in aninert atmosphere. The total or partial calcination is effected aspreviously described for the general SG synthesis.

Before the sulfidation phase, the mixed oxide precursor may require ashaping process phase, depending on the type of reactor in which it isused. Normally, the most widely used shaping techniques without theaddition of a binder are pressing, binder-free extrusion, pelletizationand agglomeration in spheroidal form by means of spray-drying and dropcoagulation techniques. For this type of application, the mostconvenient technique is extrusion, either with or without a binder. Thistechnique requires the possible addition to the material to be shaped,before extrusion and to allow the extrusion process of the material, ofa mineral or organic acid and/or a plasticizing agent and/or a porogenagent and/or an oxide which acts as binder. These techniques are knownto experts in the field and are described for example in “Extrusion inCeramics”, Handle, Frank (Eds.), Springer 2007.

With all these known techniques, it is possible to subject bothmaterials of type (A1) and materials of type (A2) to shaping process,still containing the nitrogenated compound N used in the synthesis, oran organic residue deriving therefrom by partial calcination.

An object of the present invention also relates to particular shapingprocesses for preparing shaped compounds having formula A.

In particular, an object of the present invention therefore relates to asol-gel process, for preparing compounds having formula (A), shaped, andpossibly also shaped with a binder, called SG-Form-1 process,comprising:

-   -   I) preparing a hydroalcohol solution/suspension containing at        least one soluble or partially soluble source of at least one        element X, at least one soluble or partially soluble source of        at least one element Y, at least one soluble, hydrolyzable or        dispersible source of at least one element Z and a nitrogenated        compound N selected from:        -   a) an alkyl ammonium, hydroxide having formula (I)            R^(I)R^(II)R^(III)R^(IV)NOH  (I)    -   wherein the groups R^(I)-R^(IV), the same or different, are        aliphatic groups containing from 1 to 7 carbon atoms,        -   b) an amine having formula (II)            R¹R²R³N  (II)            -   wherein R¹ is a linear, branched or cyclic alkyl,                containing from 4 to 12 carbon atoms, and    -   R² and R³, the same or different, are selected from H and a        linear, branched or cyclic alkyl, containing from 4 to 12 carbon        atoms, said alkyl being equal to, or different from, R¹;    -   II) obtaining the formation of a gel,    -   III) maintaining the gel under stirring, preferably at a        temperature ranging from 25 to 80° C., possibly after the        addition of a soluble, hydrolyzable or dispersible source of an        oxide MeO, in a weight ratio with the gel ranging from 5 to 50%        by weight with respect to the theoretical weight of the oxides        contained in the gel, and possibly after the addition of a        mineral or organic acid in a quantity ranging from 0.5 to 8.0 g        per 100 g of source of the oxide MeO, for a time sufficient for        obtaining a homogeneous paste having a consistency which is        normally considered suitable for extrusion,    -   IV) extruding the product obtained from the previous step,    -   V) drying the extruded product obtained, preferably at a        temperature ranging from 40 to 120° C.,    -   VI) at least partially calcining the extruded product obtained        in the previous step, in an oxidizing or inert atmosphere.

A preferred aspect is that steps I and II are effected as described forthe sol-gel process SG-I, steps 1-3, and for the processes SG-II-Al andSG-II-Si, steps a-c. In particular, all the aspects relating toconditions, compositions and reagents described for these steps can beused for steps I and II of the sol-gel synthesis SG-Form-1 describedabove for preparing shaped compounds having formula (A), and possiblyalso shaped with a binder.

In step III, the addition of a soluble, dispersible 25 or hydrolyzablesource of oxide MeO is optional and is always effected when the gelderiving from the previous step has a content of element Z lower than 5%with respect to the total weight of the oxides contained in the gel.Total weight of the oxides contained in the gel refers to the sum of theoxides present in the reagent mixture, calculated considering that allthe compounds X, Y, Z are transformed into the corresponding oxides.

The oxide MeO, when present, acts as binder, and a preferred aspect isfor said oxide MeO to be silicon oxide or aluminium oxide, and even morepreferably an oxide of the same element Z present in the gel. When Me isaluminium or silicon, hydrolyzable or dispersible sources of oxide MeOwhich can be suitably used in this shaping process are the same used forthe element Z in the preparation phase of the gel. When Me is silicon,for example, colloidal silicas, fumed silica and tetra-alkylorthosilicates in which the alkyl group contains from 1 to 4 carbonatoms, can be suitably used as corresponding dispersible or hydrolyzablecompounds. When Me is aluminium, monohydrated aluminas AlOOH,trihydrated aluminas Al(OH)₃, aluminium oxide, dispersible aluminas,aluminium trialkoxides wherein the alkyl is linear or branched and cancontain from 2 to 5 carbon atoms, can be suitably used.

The dispersible aluminas are preferably bohemites or pseudo-bohemitescharacterized by particles with an average diameter of less than 100microns. Dispersible aluminas which can be suitably used are for examplebohemites of the series Versal®, Pural®, Catapal®, Disperal® andDispal®.

Particularly preferred among dispersible aluminas are aluminasdispersible at room temperature in the presence of stirring in water orin aqueous solution containing a monovalent acid: in the dispersed phasethese aluminas are nanodimensional, characterized by dimensions of thedispersed particles ranging from 10 to 500 nm. Dispersible aluminas ofthis type which can be suitably used are in particular bohemites of theseries Disperal® and Dispal®.

In step III, mineral or organic acids, when used, can be:

-   -   acids already contained in the dispersible or hydrolyzable        source of oxide MeO which is added to the gel, such as for        example acetic acid, nitric acid,    -   acids contained in the gel deriving from step II if said gel has        been prepared using in step I, a dispersible or hydrolyzable        source of element Z which contains acids,    -   acids added directly in step III, if one of the previous two        hypotheses is not verified, for example acetic acid, nitric        acid, phosphoric acid or boric acid.

In step III, plasticizing agents, such as methyl cellulose, stearin,glycerine and porogen agents, such as for example soluble starch, canalso be added.

The calcination step VI is effected at a temperature lower than 450° C.,preferably lower than or equal to 400° C., if an extruded productcontaining a mixed oxide having formula (A2) is to be obtained, and at atemperature equal to or higher than 450° C., preferably higher than orequal to 450° C. and lower than or equal to 600° C., if an extrudedproduct containing a mixed oxide having formula (A1) is to be obtained.

An aspect of this particular procedure, when a hydrolyzable ordispersible source of an oxide MeO is not added, consists in the absenceof any binder which can alter the composition and physico-chemicalproperties of the oxide precursor, and consequently of the finalcatalyst.

If, when using the procedure described above, a suitable source of oxideMeO is added, at the end of the shaping process a composition containinga mixed oxide in shaped form with a binder is obtained. Said compositioncontains:

-   -   the binder MeO, in a quantity preferably higher than 5% and        lower than or equal to 50% by weight with respect to the weight        of the mixed oxide, even more preferably from 5 to 30% by weight        with respect to the weight of the mixed oxide, and wherein said        oxide MeO is preferably aluminium oxide or silicon oxide, and        even more preferably is an oxide corresponding to the element Z        contained in the gel,    -   a mixed oxide (A) essentially having the same characteristics of        porosity, surface area and structure as the corresponding mixed        oxide without a binder.

Another particular object of the present invention relates to a sol-gelprocess for preparing shaped compounds having formula (A), calledSG-Form-2, comprising:

I) preparing a hydroalcohol solution/suspension containing at least onesoluble or partially soluble source of at least one element X, at leastone soluble or partially soluble source of at least one element Y, atleast one soluble, hydrolyzable or dispersible source of at least oneelement Z and a nitrogenated compound N selected from:

-   -   a) an alkyl ammonium hydroxide having formula (I)        R^(I)R^(II)R^(III)R^(IV)NOH  (I)        -   wherein the groups R^(I)-R^(IV), the same or different, are            aliphatic groups containing from 1 to 7 carbon atoms,    -   b) an amine having formula (II)        R¹R²R³N  (II)        -   wherein R¹ is a linear, branched or cyclic alkyl, containing            from 4 to 12 carbon atoms, and R² and R³, the same or            different, are selected from H and a linear, branched or            cyclic alkyl, containing from 4 to 12 carbon atoms, said            alkyl being equal to, or different from, R¹;            II) obtaining the formation of a gel,            III) maintaining the gel at a temperature ranging from 25 to            80° C., for a time ranging from 1 to 48 hours,            IV) drying an aliquot of the gel obtained in step III,            subjecting it to at least partial calcination, and adding            it, possibly after blandly disaggregating it, to the            remaining gel as such, in a weight ratio, between at least            partially calcined product and gel as such greater than or            equal to 1,            V) extruding the product thus obtained,            VI) possibly drying the extruded product obtained, 10            preferably at a temperature ranging from 40 to 120° C. and,            VII) at least partially calcining the extruded product thus            obtained, in an oxidizing or inert atmosphere.

A preferred aspect is for steps I and II to be effected as described forthe sol-gel process SG-I, steps 1-3, and for the processes SG-II-Al andSG-II-Si, steps a-c. In particular, all the aspects relating toconditions, compositions and reagents described for these steps can beused for steps I and II of the sol-gel synthesis SG-Form-2 describedabove for preparing shaped compounds having formula (A).

Step III is preferably carried out in an open system and, depending onthe temperature and time selected, can therefore lead to a concentrationof the gel, by evaporation of the mixture of solvents.

In step IV the aliquot of gel is dried, preferably at a temperatureranging from 80 to 120° C., and calcined in air, or in an inertatmosphere. In step IV the calcinations can be effected at a temperaturelower than 450° C., preferably lower than or equal to 400° C., if amaterial containing a mixed oxide having formula (A2) is to be obtained,and at a temperature equal to or higher than 450° C., preferably higherthan or equal to 450° C. and lower than or equal to 600° C., if amaterial containing a mixed oxide having formula (A1) is to be obtained.

In step V, plasticizing agents, such as methyl cellulose, stearin,glycerine and porogen agents, such as for example soluble starch, canalso be added.

Analogously to step IV, in step VII the calcinations can be effected ata temperature lower than 450° C., preferably lower than or equal to 400°C., if 15 an extruded product containing a mixed oxide having formula(A2) is to be obtained, and at a temperature equal to or higher than450° C., preferably higher than or equal to 450° C. and lower than orequal to 600° C., if an extruded product containing a mixed oxide havingformula (A1) is to be obtained.

The mechanical characteristics of the extruded product thus obtained aresuitable for sustaining both the sulfidation phase and thermo-mechanicalstress during its use.

The fundamental aspect of this particular procedure consists in theabsence of any binder which can alter the composition andphysico-chemical properties of the precursor oxide, and consequently ofthe final catalyst.

The catalysts of the present invention obtained by sulfidation of themixed oxides having formula (A), possibly shaped without a binder, or ofmixed oxides having formula (A) in the form shaped with a binder, areextremely active catalysts and stable in hydrotreatment processes andcan be suitably used in all refining processes in which hydrotreatmentoperations must be effected, and in particular for obtaining thedesulfurization and denitrogenation of a hydrocarbon mixture.

A further object of the present invention therefore relates to a processfor the hydrotreatment of a feedstock containing one or morehydrocarbons which comprises putting said feedstock in contact with thecatalysts of the present invention obtained by sulfidation of the mixedoxides having formula (A), possibly shaped.

Any feedstock or hydrocarbon mixture containing sulfur or nitrogenimpurities can be treated with the catalysts of the present invention:oil distillates, oil residues, naphtha, light cycle oil, atmospheric gasoil, heavy gas oil, lube oil, for example, can be subjected totreatment.

With the catalysts of the present invention, it is possible to treathydrocarbon cuts containing up to 30,000 ppm of sulfur and possibly upto 2,000 ppm of nitrogen.

It is preferable to operate at a temperature ranging from 100 to 450°C., preferably from 300 to 370° C., and a pressure ranging from 50 to100 bar, preferably from 50 to 70 bar. The WHSV ranges from 0.5 to 10hours⁻¹, preferably from 1 to 2 hours⁻¹. The quantity of hydrogen canvary from 100 to 800 times the quantity of hydrocarbons, expressed asNlH₂/l of hydrocarbon mixture.

The synthesis and sol-gel processes of the precursor oxides of thecatalysts and catalytic tests are described in the following examplesbut should in no way be considered as limiting the scope of theinvention itself.

EXAMPLE 1 (COMPARATIVE)

6.62 g of octyl amine are dissolved in 40 g of absolute ethanol. Asolution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO),4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammoniummetatungstate hydrate (MTA) in 50 ml of H₂O is then added under stirringto solution A. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.5.

A light green-coloured relatively fluid gel is formed which is leftunder stirring for 3 hours, gently heating to 70° C. It is left to restfor 72 hours. The gel obtained does not have a supernatant and is leftto dry in an oven at 100° C. for 48 hours.

The dried material is calcined in air at 400° C. for 5 hours. The solidobtained has a molar composition Ni_(0.05)Mo_(0.03)W_(0.03)O_(0.23) andcontains 1.5% by weight of organic residue with respect to the totalweight. The specific surface area is 65 m²/g, the total pore volume0.228 cm³/g, the average pore diameter 7.5 nm, calculated from thedesorption isotherm.

EXAMPLE 2

9.04 g of ammonium heptamolybdate (EMA) are dissolved in 100 ml of anaqueous solution of tetrapropyl ammonium hydroxide TPAOH at 5% (solutiona). A solution consisting of 14.89 g of nickel nitrate hexhydrate (NiNO)and 4.31 g of tetraethyl orthosilicate TEOS in 80 g of absolute ethanol(solution b) is added under stirring to solution (a). The TPAOH/(Ni+Mo)molar ratio is equal to 0.25. A uniform light green-coloured fluid gelis immediately formed which is left under intensive stirring for 4 hoursat 70° C. After resting for 48 hours, the viscous gel is dried at 100°C. for 48 hours and calcined in air at 400° C. for 5 hours. The solidobtained, subjected to chemical analysis, has the following composition(weight percentage): NiO=30.7%, MoO₃=58.8%, SiO₂=10.5%.

The material obtained has a molar compositionNi_(0.05)Mo_(0.05)Si_(0.02)O_(0.23) and contains 0.1% by weight oforganic residue with respect to the total weight. The specific surfacearea is 135 m²/g, the total pore volume 0.32 cm³/g, the average porediameter 9.3 nm, calculated from the desorption isotherm.

EXAMPLE 3

7.96 g of octylamine and 4.33 g of tetraethyl orthosilicate TEOS aredissolved in 40 g of absolute ethanol (solution C). A solutionconsisting of 14.89 g of nickel nitrate hexahydrate (NiNO) and 9.04 g ofammonium heptamolybdate (EMA) in 50 ml of H₂O (solution D) is then addedunder stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio isequal to 0.6. A light green-coloured relatively fluid gel is formedwhich is left under stirring for 3 hours, gently heating to 70° C. It isleft to rest for 72 hours. The gel obtained does not have a supernatantand is left to dry in an oven at 100° C. for 48 hours. The driedmaterial is calcined in air at 400° C. for 5 hours. The solid obtained,subjected to chemical analysis, has the following composition (weightpercentage): NiO=30.7%, MoO3=59.3%, SiO2=10%.

The solid obtained has the following molar compositionNi_(0.05)Mo_(0.05)Si_(0.02)O_(0.23) and contains 1.8% by weight oforganic residue with respect to the total weight. The specific surfacearea is 123 m²/g, the total pore; volume 0.443 cm³/g, the average pore;diameter 15.9 nm, calculated from the desorption isotherm.

EXAMPLE 4

4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammoniummetatungstate hydrate (MTA) are dissolved in 100 ml of an aqueoussolution of tetrapropyl ammonium hydroxide TPAOH at 5.2% (solution a). Asolution consisting of 14.89 g of nickel nitrate hexahydrate (NiNO) and5.2 g of TEOS in 80 g of absolute ethanol (solution b) is added understirring to solution (a). The TPAOH/(Ni+Mo+W) molar ratio is equal to0.24. A uniform light green-coloured fluid gel is immediately formedwhich is left under intensive stirring for 4 hours. After resting for 48hours, the viscous gel is dried at 120° C. for 48 hours.

A quota of material is calcined in air at 400° C. for 5 hours.

The solid obtained, subjected to chemical analysis, has the followingcomposition (weight percentage): NiO=25.2%, MoO₃=23.8%, WO₃=40%,SiO₂=11%.

The solid obtained has the following molar compositionNi_(0.05)Mo_(0.03)W_(0.03)Si_(0.02)O_(0.27) and contains 0.08% by weightof organic residue with respect to the total weight. The specificsurface area is 143 m²/g, the total pore volume 0.404 cm³/g, the averagepore diameter 9.2 nm, calculated from the desorption isotherm,

Another quota of material is calcined in air at 550° C. for 5 hours. Thesolid obtained has maintained the molar formulaNi_(0.05)Mo_(0.03)Si_(0.02)O_(0.27), the specific surface area is 122m²/g, the total pore volume 0.339 cm³/g, the average pore diameter 9.4nm, calculated from the desorption isotherm.

EXAMPLE 5

8.22 g of octylamine and 5.2 g of tetraethyl orthosilicate TEOS aredissolved in 40 g of absolute ethanol (solution C). A solutionconsisting of 14.89 g of nickel nitrate hexahydrate (NiNO), 4.52 g ofammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstatehydrate (MTA) dissolved in 50 ml of H₂O (solution D) is then added understirring to solution C. The octylamine/(Ni+Mo+W) molar ratio is equal to0.6.

A light green-coloured gel is formed which is left under stirring for 3hours, gently heating to 70° C. It is left to rest for 48 hours. The gelobtained does not have a supernatant and is left to dry in an oven at100° C. for 48 hours.

A quota of material is calcined in air at 400° C. for 5 hours. The solidobtained has the following molar compositionNi_(0.05)Mo_(0.03)W_(0.03)Si_(0.03)O_(0.29) and contains 1.9% by weightof organic residue with respect to the total weight. The specificsurface area is 142 m²/g, the total pore volume 0.294 cm³/g, the averagepore diameter 5.5 nm, calculated from the desorption isotherm.

Another quota of solid is calcined in air at 550° C. for 5 hours. Theresulting solid has maintained the molar formulaNi_(0.05)Mo_(0.03)W_(0.03)Si_(0.02)O_(0.27), the specific area surfaceis 86 m²/g, the total pore volume 0.299 cm³/g, the average pore diameter11.7 nm, calculated from the desorption isotherm,

EXAMPLE 6

7.56 g of octylamine are dissolved in 40 g of absolute ethanol (solutionC). A solution consisting of 14.89 g of nickel nitrate hexahydrate(NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammoniummetatungstate hydrate (MTA) dissolved in 50 ml of an aqueous solcontaining 14.90 g of an aqueous dispersion of bohemite (Disperal® P2 ofSasol™) at 10% by weight (solution D) is then added under stirring tosolution C. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6. Alight green-coloured gel is formed which is left under stirring for 3hours, heating to 70° C. It is left to rest for 48 hours. The gelobtained does not have a supernatant and is left to dry in an oven at90° C. for 48 hours. The dried material is subjected to calcinationtreatments in air at different temperatures: 200, 300 and 400° C. for 5hours.

The fraction of residual organic component on the sample depends on thethermal treatment to which it is subjected. The table indicates theweight percentage of organic residue, with respect to the total weightof the solid, in relation to the final temperature of the thermalcalcination treatment.

Weight % of organic residue with respect to the total weight ofTemperature (° C.) the solid* (% w/w) 200 7.7 300 5.4 400 2.0 *theorganic residue was calculated from the weight loss between 200-600° C.,measured by TGA analysis, on the materials precalcined at thetemperature indicated.

The solid obtained after calcination at 400° C. in air for 5 hours,called sample C, has the following molar compositionNi_(0.05)Mo_(0.03)W_(0.03)Al_(0.03)O_(0.28) and contains 2.0% by weightof organic residue with respect to the total weight of the solid. Thespecific surface area is 151 m²/g, the total pore volume 0.381 cm³/g,the average pore diameter 6.3 nm, calculated from the desorptionisotherm.

EXAMPLE 7

4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammoniummetatungstate hydrate (MTA) are dissolved in 100 ml of an aqueoussolution of tetrapropyl ammonium hydroxide TPAOH at 5.2% (solution a). Asolution consisting of 14.9 g of cobalt nitrate hexhydrate (CoNO) and5.2 g of TEOS in 80 g of absolute ethanol (solution b) is added understirring to solution (a). The TPAOH/(Ni+Mo+W) molar ratio is equal to0.24.

A uniform purple-coloured fluid gel is immediately formed which is leftunder intensive stirring for 4 hours, heating to 70° C. It is left torest for 3 days and is finally dried at 100° C. for 72 hours andcalcined in air at 400° C. for 5 hours.

The solid obtained, subjected to chemical analysis, has the followingcomposition (weight percentage): CoO=24.8%, MoO₃=23.8%, Wo₃=41.4%,SiO₂=10%.

The solid obtained has the following molar compositionCo_(0.05)Mo_(0.03)W_(0.03)Si_(0.03)O_(0.29) and contains 0.1% by weightof organic residue with respect to the total weight.

The specific surface area is 115 m²/g, the total pore volume 0.255cm³/g, the average pore diameter 9.1 nm, calculated from the desorptionisotherm.

EXAMPLE 8

8.22 g of octylamine and 5.2 g of tetraethyl orthosilicate TEOS aredissolved in 40 g of absolute ethanol (solution C). A solutionconsisting of 14.9 g of cobalt nitrate hexahydrate (CoNO), 4.52 g ofammonium heptamolybdate (EMA) and 6.98 g of ammonium metatungstatehydrate (MTA) dissolved in 50 ml of H₂O (solution D) is then added understirring to solution C. The octylamine/(Co+Mo+W) molar ratio is equal to0.6.

A purple gel is formed which is left under stirring for 3 hours at 70°C. It is left to rest for 48 hours. The gel obtained is dried in an ovenat 90-100° C. for 48 hours. The dried material is calcined in air at400° C. for 5 hours.

The solid obtained, subjected to chemical analysis, has the followingcomposition (weight percentage): CoO=24.7%, MoO₃=24.2%, WO₃=41.1%,SiO₂=10%.

The solid obtained has the following molar compositionCo_(0.05)Mo_(0.03)W_(0.03)Si_(0.03)O_(0.29) and contains 2.1% by weightof organic residue with respect to the total weight.

The specific surface area is 90 m²/g, the total pore volume 0.182 cm³/g,the average pore diameter 4.8 5 nm, calculated from the desorptionisotherm.

EXAMPLE 9

7.56 g of octylamine are dissolved in 80 g of absolute ethanol (solutionC). A solution consisting of 12.74 g of nickel acetate tetrahydrate(NiAc), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammonium,metatungstate hydrate (MTA) dissolved in 200 ml of an aqueous solcontaining 14.9 g of an aqueous dispersion at 0.6% in acetic acid ofbohemite (Disperal® P3 of Sasol™) at 10% by weight (solution D) is thenadded under stirring to solution C. The octylamine/(Ni+Mo+W) molar ratiois equal to 0.6.

A light green-coloured gel is formed which is left under stirring for 8hours, heating to 70° C. It is left to rest for 48 hours. The gel isdried in an oven at 80° C. for 48 hours.

The dried material is subjected to calcination treatment in air at 400°C. for 5 hours.

The solid obtained has the following molar compositionNi_(0.05)MO_(0.03)W_(0.03)Al_(0.03)O_(0.28) and contains 2.2% by weightof organic residue with respect to the total weight. The specificsurface area is 111 m²/g, the total pore volume 0.19 cm³/g, the averagepore diameter 3.7 nm, calculated from, the desorption isotherm.

EXAMPLE 10

8.98 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al₂O₃) are dispersed in100 g of demineralized H₂O. 89.34 g of nickel nitrate hexahydrate(NiNO), 27.12 g of ammonium heptamolybdate (EMA) and 41.88 g of ammoniummetatungstate hydrate (MTA) are added to the dispersion in order and themixture is brought to a volume of about 300 ml with demineralized H₂O.

45.30 g of octylamine (99% w/w) are diluted in 240 g of absolute ethanoland subsequently added to the dispersion. The gel formed is heated,under stirring to 70° C. in an open beaker for 14 hours and isconcentrated until a homogeneous gel is obtained, which is left to agefor 40 hours. The octylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

Half of the gel is dried and calcined at 400° C. The solid obtained hasthe following molar compositionNi_(0.15)Mo_(0.08)W_(0.09)Al_(0.06)O_(0.75) and contains 2.1% by weightof organic residue with respect to the total weight. The remaining gelis introduced into a Brabender mixer.

60 g of Bohemite SASOL DISPERSAL P2 and 30 ml of H₂O are added, undermixing, at 50 rpm. The mixture is heated to 80° C. for about 3 hoursuntil a homogeneous paste with a suitable consistency for beingextruded, is obtained. The mixture is cooled and the compound isdischarged and extruded with a Hosokawa extruder of the Hutt type havinga diameter of the holes of 1.5 mm. The extruded product is left to ageat room temperature for a night, then dried in a static oven at 90° C.for 5 hours and calcined in a flow of air according to the followingprogram:

from room temperature to 100° C. with a rise of 2° C./min, at 100° C.for 5 hours then at 120° C., 2° C./min, for 5 hours, at 130° C., 2°C./min, for 5 hours, at 160° C., 2° C./min, for 5 hours, at 200° C., 2°C./min, for 5 hours and at 400° C., 2° C./min, for 10 hours.

The final extruded product consists of 50% by weight of mixed oxide and50% by weight of alumina binder.

The extruded product has a good mechanical resistance.

EXAMPLE 11 (COMPARATIVE)

An extruded product is prepared using a reaction mixture in which theoctylamine/(Ni+Mo+W) molar ratio is equal to 1.5.

69.1 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al₂O₃) are dispersed in300 g of demineralized H₂O.

53.5 g of nickel nitrate hexahydrate (NiNO), 16.2 g of ammoniumheptamolybdate (EMA) and 25.1 g of ammonium metatungstate hydrate (MTA)are added to the dispersion in order and the mixture is brought to avolume of about 500 ml with demineralized H₂O.

75.60 g of octylamine (99% w/w) are diluted in 400 g of absolute ethanoland subsequently added to the dispersion. The octylamine/(Ni+Mo+W) molarratio is equal to 1.6.

The gel formed is heated, under stirring to about 70° C. in an openbeaker for 16 hours. It is left under static conditions for a night. Thegel is introduced into a Brabender mixer and mixed at 50 rpm at 50° C.for 0.5 hours and at 80° C. for 3 hours until a paste is obtained,suitable for being extruded with a Hosokawa extruder of the Hutt typehaving a diameter of the holes of 1.5 mm. The extruded product is leftto age at room temperature for a night, then dried in a static oven at90° C. for 5 hours and calcined in a flow of air according to thefollowing program:

from room temperature to 100° C. with a rise of 2° C./min, at 100° C.for 5 hours then at 120° C., 2° C./min, for 5 hours, at 130° C., 2°C./min, for 5 hours, at 160° C., 2° C./min, for 5 hours, at 200° C., 2°C./min, for 5 hours and at 400° C., 2° C./min, for 10 hours.

EXAMPLE 12

76.1 g of octylamine and 48.1 g of tetraethyl orthosilicate TEOS aredissolved in 370 g of absolute ethanol (solution C). A solutionconsisting of 137.9 g of nickel nitrate hexahydrate (NiNO), 41.9 g ofammonium heptamolybdate (EMA) and 64.6 g of ammonium metatungstatehydrate (MTA) dissolved in 460 ml of H₂O (solution D) is then addedunder stirring to solution C. The octylamine/(Ni+Mo+W) molar ratio isequal to 0.6.

A light green-coloured gel is formed which is concentrated to 600 g byevaporation at 80° C. After 48 hours of resting, 80 g of the gelobtained are collected. A solid is obtained from the remaining quantitywhich can be easily pulverized, after drying at 100° C. for 48 hours andcalcination in air at 400° C. for 5 hours.

The solid obtained has the following molar compositionNi_(0.41)Mo_(0.21)W_(0.23)Si_(0.20)O_(2.13) and contains 2.2% by weightof organic residue with respect to the total weight.

120 g of this calcined powder are amalgamated with the 80 g of gelpreviously collected and the homogeneous paste thus obtained is drawndirectly at room temperature in a Brabender extruder. Rigid formulatesare obtained with a specifically regulated sizing of 5 mm in length and1.5 mm in diameter. After calcination at 400° C. for 5 hours, a materialwith a good mechanical resistance is obtained.

The extruded product obtained has a surface area equal to 136 m²/g, atotal pore volume of 0.26 cm³/g and an average pore diameter of 7.4 nm,calculated from the desorption isotherm.

EXAMPLE 13

54 g of Bohemite SASOL DISPERSAL P2 (73% w/w Al₂O₃) are dispersed in 600g of demineralized H₂O.

554 g of nickel nitrate hexahydrate (NiNO), 162 g of ammoniumheptamolybdate (EMA) and 251 g of ammonium metatungstate hydrate (MTA)are added to the dispersion in order and the mixture is brought to avolume of about 1,800 ml with demineralized H₂O.

271 g of octylamine are diluted in 1,440 g of absolute ethanol andsubsequently added to the dispersion.

The gel formed is heated, under stirring to 60° C. for 15 hours and agedat room temperature for 20 hours. The octylamine/(Ni+Mo+W) molar ratiois equal to 0.5.

630 g of gel are obtained. 50 g of gel are dried and calcined at 400° C.The solid obtained has the following molar compositionNi_(0.15)Mo_(0.08)W_(0.08)Al_(0.06)O_(0.72) and contains 2.2% by weightof organic residue with respect to the total weight.

140 g of Bohemite SASOL DISPERSAL P2 and 30 ml of H₂O are added, understirring at 50 rpm.

The mixture is heated to 80° C. for about 3 hours until a homogeneouspaste having a consistency suitable for extrusion, is obtained. Theoctylamine/(Ni+Mo+W) molar ratio is equal to 0.5.

The mixture is cooled and the compound is discharged and extruded with aHosokawa extruder of the Hutt type having a hole diameter of 1.5 mm.

The extruded product is left to age at room temperature for a night,then dried in a static oven at 90° C. for 5 hours and calcined in a flowof air with a temperature rise of 2° C./min and the following steps:

110° C. for 16 hours, 120° C. for 1 hour, 140° C. for 1 hour, 160° C.for 10 hours, 400° C. for 10 hours, in air.

The final extruded product consists of 80% by weight of mixed oxide and20% by weight of alumina binder.

The organic residue, calculated from the weight loss between 200-600°C., measured by means of TGA analysis, is equal to 2.4% by weight withrespect to the total weight of the extruded product.

The extruded product has a good mechanical resistance.

EXAMPLES 14-15

The material obtained in Example 1 and the material obtained in Example6 by calcination at 400° C. (sample C), were used as catalysts in thefollowing hydrotreatment catalytic test.

The fixed bed reactor is charged with 5 grams of catalyst previouslypressed and granulated (20-40 mesh).

The process takes place in 2 phases: sulfidation of the catalyst andhydrotreatment step.

a) Sulfidation

The catalyst is treated with a sulfiding mixture consisting of StraightRun Gasoil, with the addition of Dimethyl disulfide, so as to have aconcentration of S equal to 2.5 by weight with respect to the totalweight of the sulfiding mixture. The sulfidation conditions used are:

LHSV=3 hours⁻¹

P=30 bar

T=340° C.

H₂/sulfiding mixture=200 Nl/l.

b) Hydrotreatment

The reaction is carried out under the following conditions:

T=320° C.

P=60 bar

Liquid feedstock flow-rate: 8 ml/hour

H₂ flow-rate: 5 Nl/hour

WHSV=1.35 hour⁻¹

The feedstock stream consists of gasoil coming from thermal cracking andcontains 23,900 ppm of sulfur and 468 ppm of nitrogen. The activity ofthe catalysts is expressed as hydrodenitrogenation (HDN) andhydrodesulfurization (HDS) conversion.

After 120 hours, the conversion, data indicated in the following tablewere measured:

Example Catalyst HDN HDS 14 Ex. 1 (comparative) 71.5 90.6 15 Ex. 6 81.092.5

As is evident from comparing the results, the material of the presentinvention is much more active.

EXAMPLES 16-17

The sulfidation and hydrotreatment test are carried out as described forExamples 14-15.

A comparison is made of the catalysts obtained in Examples 10 and 11;the following table indicates the data measured at 320° C., after 120hours. The activity of the catalysts is expressed ashydrodenitrogenation (HDN) and hydrodesulfurization (HDS) conversion.

Example Catalyst HDN HDS 16 Ex. 10 66.7 92.5 17 Ex. 11 (comparative)63.3 86.2

It is evident that upon increasing the content of nitrogenated compoundin the synthesis, less active materials are obtained in thehydrotreatment.

EXAMPLES 18-19

The sulfidation was carried out as described for Examples 14-15. Thehydrotreatment reaction is carried out under the following conditions:

T=340° C.

P=60 bar

Liquid feedstock flow-rate: 8 ml/hour

H₂ flow-rate: 5 Nl/hour

WHSV=1.35 hour⁻¹

The hydrocarbon feedstock used is gasoil coming from thermal crackingand contains 23,900 ppm of sulfur and 468 ppm of nitrogen.

A comparison is made of the catalysts obtained in Examples 12 and 13.The following table indicates the conversion data measured at thereaction temperature of 340° C., after 180 hours. The activity of thecatalysts is expressed as hydrodenitrogenation (HDN) andhydrodesulfurization (HDS) conversion.

Example Catalyst HDN HDS 18 Ex. 12 99.5 99.5 19 Ex. 13 90.6 98.0

The optimum performances of the materials of the present invention areevident.

EXAMPLE 20

The catalyst of Example 6 is sulfided as described in Examples 14-15 andused for the hydrotreatment of gasoil coming from thermal cracking whichcontains 23,900 ppm of sulfur and 468 ppm of nitrogen.

The hydrotreatment conditions are the following:

T=340° C.

P=60 bar

Liquid feedstock flow-rate: 8 ml/hour

H₂ flow-rate: 5 Nl/hour

WHSV=1.35 hour⁻¹

The activity of the catalyst is expressed as hydrodenitrogenation (HDN)and hydrodesulfurization (HDS) conversion.

After 180 hours at the reaction temperature of 340° C., the followingconversion data are obtained:

HDS=99.5

HDN=99.4

EXAMPLE 21

5.92 g of hexylamine are dissolved in 40 g of absolute ethanol (solutionC). A solution consisting of 14.89 g of nickel nitrate hexahydrate(NiNO), 4.52 g of ammonium heptamolybdate (EMA) and 6.98 g of ammoniummetatungstate hydrate (MTA) dissolved in 50 ml of an aqueous solcontaining 14.9 g of an aqueous dispersion of bohemite (Disperal® P2 ofSasol™) at 10% by weight (solution D) is then added under stirring tosolution C. The hexylamine/(Ni+Mo+W) molar ratio is equal to 0.6.

A light green-coloured gel is formed, which is left under stirring for 3hours, heating to 70° C. It is left to rest for 48 hours. The gelobtained does not have a supernatant, and is dried in an oven at 90° C.for 48 hours.

The solid obtained after calcination in air at 400° C. for 5 hours has aspecific surface area of 140 m²/g, a total pore volume of 0.400 cm³/g,am average pore diameter of 7.5 nm, calculated from the desorptionisotherm.

The solid obtained after calcination in air at 550° C. for 5 hours has amolar composition Ni_(0.05)Mo_(0.03)W_(0.03)Si_(0.02)O_(0.27), aspecific surface area of 86 m²/g, a total pore volume of 0.346 cm³/g, anaverage pore diameter 11.0 nm, calculated from the desorption isotherm.

The invention claimed is:
 1. A sol-gel process for preparing a mixedoxide of formula (A), comprising: preparing a hydroalcoholsolution/suspension comprising at least one soluble or partially solublesource of at least one element X, at least one soluble or partiallysoluble source of at least one element Y, at least one soluble source,which can be hydrolyzed or dispersed, of at least one element Z and anitrogenated compound N selected from: a) an alkyl ammonium hydroxide offormula (I)R^(I)R^(II)R^(III)R^(IV)NOH  (I) wherein R^(I), R^(II), R^(III) andR^(IV) are the same or different and are aliphatic groups containingfrom 1 to 7 carbon atoms, b) an amine of formula (II)R¹R²R³N  (II) wherein R¹ is a linear, branched or cyclic alkyl,containing from 4 to 12 carbon atoms, and R² and R³ are the same ordifferent and are selected from H and a linear, branched or cyclicalkyl, containing from 4 to 12 carbon atoms, said alkyl being equal to,or different from, R¹; wherein the molar ratio N/(X+Y) is greater than0.1 and less than, or equal to 1, obtaining the formation of a gel,maintaining the gel under stirring, maintaining the gel under staticconditions, drying the gel prepared in the previous step, obtaining themixed oxide precursor of formula (A2)X_(a)Y_(b)Z_(c)O_(d) .pC  (A2) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z isselected from Si, Al or a mixture thereof, O is oxygen, C is anitrogenated compound N selected from the nitrogenated compoundsmentioned above, having formula (I) or (II), a, b, c, d are the numberof moles of the elements X, Y, Z and O, respectively, p is the weightpercentage of C with respect to the total weight of the compound havingformula (A2) a, b, c, d are greater than 0 a/b is greater than or equalto 0.3 and less than or equal to 2, (a+b)/c is greater than or equal to0.8 and less than or equal to 10 when Z is Si or a mixture of Si and Al,but is greater than or equal to 0.3 and less than or equal to 10 when Zis Al, d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al and p isgreater than 0 and less than or equal to 40%, optionally subjecting thecompound of formula (A2) resulting from the previous step, to partial ortotal calcination, respectively obtaining a compound having the sameformula (A2) wherein C is an organic residue deriving from thecalcination of the nitrogenated compound, or a mixed oxide of formula(A1)X_(a)Y_(b)Z_(c)O_(d)  (A1) wherein X, Y, Z, O, a, b, c, d correspond tothose of the previous formula (A2); and wherein said mixed oxide offormula (A) has the formula:X_(a)Y_(b)Z_(c)O_(d) .pC  (A) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z isselected from Si, Al or a mixture thereof, O is oxygen C is selectedfrom: a nitrogenated compound N, an organic residue deriving from thenitrogenated compound N by partial calcination, wherein saidnitrogenated compound N is selected from: a) an alkyl ammonium hydroxideof the formula (I)R^(I)R^(II)R^(III)R^(IV)NOH  (I) wherein the groups R^(I), R^(II),R^(III) and R^(IV) are the same or different and are aliphatic groupscontaining from 1 to 7 carbon atoms, b) an amine having formula (II)R¹R²R³N  (II) wherein R¹ is a linear, branched or cyclic alkyl,containing from 4 to 12 carbon atoms, and R² and R³ are the same ordifferent and are selected from H and a linear, branched or cyclicalkyl, containing from 4 to 12 carbon atoms, said alkyl being equal toor different from R¹ a, b, c, d are the number of moles of the elementsX, Y, Z, O, respectively, p is the weight percentage of C with respectto the total weight of the compound having formula (A), a, b, c, d aregreater than 0 a/b is greater than or equal to 0.3 and less than orequal to 2, (a+b)/c is greater than or equal to 0.8 and less than orequal to 10 when Z is Si or a mixture of Si and Al, but is greater thanor equal to 0.3 and less than or equal to 10 when Z is Al,d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al and p is greater thanor equal to 0 and less than or equal to 40%.
 2. The process according toclaim 1, wherein, when Z is silicon, the corresponding solublecompounds, which can be dispersed or hydrolyzed, are colloidal silica,fumed silica and tetraalkyl ortho silicates wherein the alkyl groupcontains from 1 to 4 carbon atoms.
 3. The process according to claim 1,wherein, when Z is aluminium, the corresponding soluble compound isaluminium lactate and the corresponding dispersible or hydrolyzablecompounds are dispersible aluminas, monohydrated aluminas AlOOH,trihydrated aluminas Al(OH)₃, aluminium oxide, aluminium trialkoxideswherein the alkyl is linear or branched and can contain from 2 to 5carbon atoms.
 4. The process according to claim 1, wherein, in the laststep, the total calcination is effected at a temperature of at least450° C.
 5. The process according to claim 4, wherein the totalcalcination is effected at a temperature higher than or equal to 450° C.and lower than or equal to 600° C.
 6. The process according to claim 1,wherein the calcination is effected partially and at a temperature lowerthan 450° C.
 7. The process according to claim 6, wherein the partialcalcination is effected at a temperature ranging from 200 to 400° C. 8.The process according to claim 1, comprising the following steps: 1) anaqueous solution (a) is prepared of at least one soluble or partiallysoluble source of at least one metal Y, and alkyl ammonium hydroxide, offormulaR^(I)R^(II)R^(III)R^(IV)NOH  (I) wherein the groups R^(I)-R^(IV) are thesame or different and are aliphatic groups containing from 1 to 7 carbonatoms, is added to this solution, 2) a solution/suspension (b) inalcohol is prepared, of a hydrolyzable or dispersible soluble compoundof the element Z and of at least a soluble or partially soluble sourceof at least one metal X; 3) the solution (a) and the solution/dispersion(b) are mixed, obtaining the formation of a gel; 4) this gel ismaintained under stirring, 5) the gel is maintained under staticconditions, 6) the gel resulting from step (5) is dried, obtaining amixed oxide of formula (A2)X_(a)Y_(b)Z_(c)O_(d) .pC  (A2) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z isselected from Si, Al or a mixture thereof, O is oxygen, C is anitrogenated compound of formula (I), a, b, c, d are the number of molesof the elements X, Y, Z and O, respectively, p is the weight percentageof C with respect to the total weight of the compound of formula (A2) a,b, c, d are greater than 0 a/b is greater than or equal to 0.3 and lessthan or equal to 2, (a+b)/c is greater than or equal to 0.8 and lessthan or equal to 10, d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Alp is greater than 0 and less than or equal to 40%, 7) the productobtained from step (6) is optionally subjected to partial or totalcalcination, obtaining, respectively, a compound having the same formula(A2) wherein C is an organic residue deriving from the calcination ofthe nitrogenated compound, or a mixed oxide of formula (A1):X_(a)Y_(b)Z_(c)O_(d)  (A1) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z isselected from Si, Al or a mixture thereof, O is oxygen a, b, c, d arethe number of moles of the elements X, Y, Z, O, respectively and aregreater than 0 a/b is greater than or equal to 0.3 and less or equal to2, (a+b)/c is greater than or equal to 0.8 and less than or equal to 10d=(2a+6b+Hc)/2 wherein H=4 when Z=Si H=3 when Z=Al.
 9. The processaccording to claim 8, wherein, in step (3), the ratios between thereagents, expressed as molar ratios of the elements, are the following:X/Y=0.3-2R^(I)R^(II)R^(III)R^(IV)NOH/(X+Y)=0.1-0.6 (X+Y)/Z is greater than orequal to 0.8 and less than or equal to 10H₂O/(X+Y+Z)>10Alcohol/H₂O=0-1.
 10. The process according to claim 9, wherein thefollowing molar ratios between the elements in step (3) are used:X/Y=0.3-2R^(I)R^(II)R^(III)R^(IV)NOH/(X+Y)=0.1-0.4 (X+Y)/Z is greater than orequal to 0.8 and less than or equal to 10H₂O/(X+Y+Z)>10Alcohol/H₂O=0.1-0.6.
 11. The process according to claim 1, for preparinga compound of formula (A) wherein (Z) is silicon, comprising thefollowing phases: a) a solution (C) is prepared in alcohol, of ahydrolyzable or dispersible compound of silicon, and an amine is alsoadded to this solution, said amine having formula (II)R¹R²R³N  (II) wherein R¹ is a linear, branched or cyclic alkyl,containing from 4 to 12 carbon atoms, and R² and R³ are the same ordifferent and are selected from H and a linear, branched or cyclic alkylcontaining from 4 to 12 carbon atoms, said alkyl being the same ordifferent from R^(I); b) a solution/aqueous suspension (D) is preparedof at least one source of at least one metal X and of at least onesource of at least one metal Y; c) the solution (C) and thesolution/suspension (D) are stirred until a gel is formed; d) the gel ismaintained under stirring, e) the gel is maintained under staticconditions, f) the gel resulting from step (e) is dried, obtaining amixed oxide precursor of formula (A2)X_(a)Y_(b)Z_(c)O_(d) .pC  (A2) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Si,O is oxygen, C is a nitrogenated compound having formula (II), a, b, c,d are the number of moles of the elements X, Y, Z and O, respectively, pis the weight percentage of C with respect to the total weight of thecompound of formula (A2) a, b, c, d are greater than 0 a/b is greaterthan or equal to 0.3 and less than or equal to 2, (a+b)/c is greaterthan or equal to 0.8 and less than or equal to 10, d=(2a+6b+Hc)/2wherein H=4 p is greater than 0 and less than or equal to 40%, g) theproduct obtained in the previous step is optionally subjected to partialor total calcination, obtaining, respectively, a mixed oxide having thesame formula (A2) wherein C is an organic residue deriving from thepartial calcination of the nitrogenated compound N, or a mixed oxide offormula (A1):X_(a)Y_(b)Z_(c)O_(d)  (A1) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z is SiO is oxygen a, b, c, d are the number of moles of the elements X, Y, Z,O, respectively a, b, c, d are greater than 0 a/b is greater than orequal to 0.3 and less than or equal to 2, (a+b)/c is greater than orequal to 0.8 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=4.12. The process according to claim 11, wherein the following molarratios between the elements of step (3) are used:X/Y=0.3-2R¹R²R³N/(X+Y)=0.1-1 (X+Y)/Si is greater than or equal to 0.8 and lessthan or equal to 10H₂O/(X+Y+Si)>10Alcohol/H₂O=0-0.4.
 13. The process according to claim 1, for preparingcompounds having formula (A) wherein (Z) is aluminum, comprising thefollowing phases: a) a solution (C) is prepared in alcohol, of an amineof formula (II)R¹R²R³N  (II) wherein R¹ is a linear, branched or cyclic alkyl,containing from 4 to 12 carbon atoms, and R² and R³ are the same ordifferent and are selected from H and a linear, branched or cyclic alkylcontaining from 4 to 12 carbon atoms, said alkyl being the same ordifferent from R^(I); b) a solution/aqueous suspension (D) is preparedof soluble or partially soluble sources of at least one metal X, atleast one metal Y and a hydrolyzable compound of aluminum; c) thesolution (C) and the solution/suspension (D) are mixed until a gel isformed; d) the gel is maintained under stirring, e) the gel ismaintained under static conditions, f) the gel resulting from step (e)is dried, obtaining a precursor mixed oxide of formula (A2)X_(a)Y_(b)Z_(c)O_(d) .pC  (A2) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z is Al,O is oxygen, C is a nitrogenated compound of formula (II), a, b, c, dare the number of moles of the elements X, Y, Z and O, respectively, pis the weight percentage of C with respect to the total weight of thecompound of formula (A2) a, b, c, d are greater than 0 a/b is greaterthan or equal to 0.3 and less than or equal to 2, (a+b)/c is greaterthan or equal to 0.3 and less than or equal to 10, d=(2a+6b+Hc)/2wherein H=3 p is greater than 0 and less than or equal to 40%, g) theproduct obtained in the previous step is optionally subjected to partialor total calcination, obtaining, respectively, a mixed oxide having thesame formula (A2) wherein C is an organic residue deriving from thepartial calcination of the nitrogenated compound, or a mixed oxide offormula (A1):X_(a)Y_(b)Z_(c)O_(d)  (A1) wherein X is selected from Ni, Co or amixture thereof, Y is selected from Mo, W or a mixture thereof, Z is AlO is oxygen a, b, c, d are the number of moles of the elements X, Y, Z,O, respectively a, b, c, d are greater than 0 a/b is greater than orequal to 0.3 and less than or equal to 2, (a+b)/c is greater than orequal to 0.3 and less than or equal to 10, d=(2a+6b+Hc)/2 wherein H=3.14. The process according to claim 13, wherein, in phase (c), the ratiosbetween the reagents, expressed as molar ratios between the elements,are the following:X/Y=0.3-2R¹R²R³N/(X+Y)=0.1-1 (X+Y)/Al is higher than or equal to 0.3 and lowerthan or equal to 10H₂O/(X+Y+Al)>10Alcohol/H₂O=0-1.